For those readers newly interested in astronomy, Sheehan offers an accessible history of the men who collected data about Mars and interpreted it. It's a little slow in starting; the earliest sections betray amateur astronomer Sheehan's fascination with the history of optics: ""One of these triplet lenses with a 3.75-inch (95-mm) aperture was purchased by Neville Maskelyne for the Royal Observatory at Greenwich, and another, of 3.8 inches (97mm), was acquired by the wealthy connoisseur,"" etc., etc. And it's also hard to believe that most general readers' interest will be sustained through albedo studies or his explanation of the Martian seasons. But what is arguably the central story is the coherent and compelling narrative of Giovanni Schiaparelli, Percival Lowell and the description of the ""canals"" of Mars, dark markings that Schiaparelli described and Lowell posited were a civilized society's attempts to harness water from melting polar caps. Sheehan points out that with the canals and the Martians who built them disproven and astrophysics on the rise, planetary astronomy suffered from neglect. The timing of Sheehan's (Planets and Perception) book was right on and slightly off. He missed the announcement of the discovery of what may be chemical and fossil evidence of life in the Martian rock ALH84001; but much of his history is concerned with the chimerical promise of life on the planet. ""The odds of finding living organisms on Mars were obviously very slim,"" he says later in the book, ""but it seemed that they might not be nil."" Astronomy Book Club main. (Oct.)